Extract derivative calculation logic from GeomEvaluator and
Geom2dEvaluator classes into dedicated utility headers:
- Geom_OffsetSurfaceUtils.pxx for 3D offset surface derivatives
- Geom_OffsetCurveUtils.pxx for 3D offset curve derivatives
- Geom2d_OffsetCurveUtils.pxx for 2D offset curve derivatives
- Geom_ExtrusionUtils.pxx for extrusion surface calculations
- Geom_RevolutionUtils.pxx for revolution surface calculations
Utility functions provide unified handling of singular and non-singular
cases with osculating surface support for higher-order derivatives.
Buffer management uses NCollection_LocalArray for stack-safe allocation
with heap fallback when sizes exceed expected limits.
Test case expectations updated to reflect improved calculation accuracy.
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